1. Field of the Invention
This invention relates to high solids coating and/or impregnating compositions, curable at ambient conditions, containing a film-forming component, a low molecular weight polymer containing units from dicyclopentenyl methacrylate and/or dicyclopentenyloxyalkyl methacrylate, a polyvalent metal salt or complex, and, optionally, a reactive, non-volatile diluent monomer.
Interest in the preservation of the environmental quality and in the conservation of energy, manifested by governmental implementation of increasingly stringent anti-pollution and energy conservation regulations, has generated considerable interest in the use of reactive diluents in coating compositions. These diluents are generally high boiling, low viscosity monomers that function as solvents during application but undergo cure of some kind, especially preferably under ambient conditions, and thereby become an integral part of the product coating. Pollution attributable to conventional solvent emissions is thereby reduced or eliminated and the necessity of a source of heat to evaporate solvent from the applied coating composition and to effect cure thereof is also thereby obviated.
2. Description of Relevant Art
Emmons, Nyi and Sperry, U.S. Pat. No. 4,071,489, issued Jan. 31, 1978, disclose air-drying coating compositions based on alkyd resins comprising at least one of dicyclopentenyl methacrylate or dicyclopentenyl acrylate, and a polyester or an alkyd resin having at least one unsaturated component curable by the addition thereto of a drier or a siccative, the composition optionally containing a volatile oxime stabilizer to prevent the oxidizing action of the drier when it is included in the composition prior to storage. The composition may optionally include addition and condensation polymers (see col. 6, lines 36-41).
Emmons, Nyi and Sperry, U.S. Pat. No. 4,100,133, issued July 11, 1978, disclose autoxidizable compositions comprising at least one of dicyclopentenyl methacrylate or dicyclopentenyl acrylate, a copolymer containing at least one of dicyclopentenyl methacrylate and dicyclopentenyl acrylate, a siccative, and a volatile oxime stabilizer. The patent also discloses cured film products thereof. The optional inclusion of an addition or condensation polymer is described at col. 5, lines 30-35.
Emmons, Nyi and Sperry, U.S. Pat. No. 4,138,390, issued Feb. 6, 1979, disclose autoxidizable compositions comprising at least one of dicyclopentenyl methacrylate and dicyclopentenyl acrylate, a film-forming vinyl addition polymer having a molecular weight of 20,000 to 350,000 amu, a drier, and a volatile oxime stabilizer. the patent also discloses air-dried film products thereof.
Emmons, Nyi and Sperry, U.S. Pat. No. 4,131,580, issued Dec. 26, 1978, relates to film-forming polymer dispersions comprising aqueous solutions of polymers of monoethylenically unsaturated monomers (as well as dispersions) plus dicyclopentenyl acrylate or methacrylate and a drier.
Emmons and Nyi, U.S. Pat. No. 4,097,677, issued June 2, 1978, discloses, as reactive, non-volatile monomers, dicyclopentenyloxyalkyl methacrylate and dicyclopentenyloxyalkyl acrylate, which are useful in the production of polymers, in coating and/or impregnating compositions, and/or in molding, casting, or otherwise forming shaped articles. The patent discusses generally the use of these reactive, non-volatile monomers in certain alkyd resins in combination with a polymeric material and a drier. The amounts of polymeric material may be from 0.5 to 25% by weight based on the total weight of monomer and alkyd resin (see col. 8, lines 8-25). It is also noted that these monomers from linear homopolymers and copolymers (with other monoethylenically unsaturated monomers) while leaving the unsaturation of the dicyclopentenyl ring intact (see col. 2, lines 54-57). Examples 15-17 discuss homopolymers and copolymers of dicyclopentenyloxyethyl methacrylate. Examples 18-20 describe coating compositions containing the polymers of Examples 15-17 plus dicyclopentenyloxyethyl methacrylate monomer and a drier (conditions C and D--see Table D). None of these compositions contains an alkyd resin or drying oil component.
Emmons and Nyi, U.S. Pat. No. 4,145,503, issued Mar. 20, 1979, which is a continuation-in-part of the application which issued as U.S. Pat. No. 4,097,677, and Emmons and Nyi, U.S. patent application Ser. No. 908,427, filed May 22, 1978 now U.S. Pat. No. 4,261,782 issued Apr. 14, 1981, which is a continuation-in-part of the application which issued as U.S. Pat. No. 4,145,503, disclose coating and/or impregnating compositions, curable by autoxidation, of at least one of dicyclopentenyloxyalkyl methacrylate or dicyclopentenyloxyalkyl acrylate, a drying oil or a film-forming addition or condensation polymer, a siccative, and, optionally, a volatile oxime stabilizer. The film-forming polymer may be an alkyd resin having an autoxidative functionality, a condensation polymer modified with an acrylate or methacrylate functionality as end groups or pendant groups, or a vinyl addition polymer (including copolymers of dicyclopentenyl acrylate or methacrylate). The film-forming polymer may have a molecular weight in the range of from about 500 to about 15,000 amu (col. 4, lines 15-17).
Although the use of dicyclopentenyloxyalkyl methacrylates has presented improvement in the class of reactive diluent monomers, further improvement is desired. In some applications, especially those conducted at ambient temperature, that is, 0.degree.-100.degree. F., dicyclopentenyloxyalkyl methacrylates, for example, dicyclopentenyloxethyl methacrylate, and compositions based thereon cure more slowly than is desirable. This slow cure rate is believed to be caused, in part, by oxygen inhibition of homopolymerization, a phenomenon well established with methacrylate monomers as reported by F. R. Mayo and A. A. Miller, J. Amer. Chem Soc., 80, 2493 (1958). While oxygen is needed by the methacrylate monomer to form the hydroperoxide requisite for homopolymerization, excessively high oxygen concentration results in the slow formation of a copolymer containing alternating units of oxygen and the methacrylate monomer rather than in rapid homopolymerization of the methacrylate monomer-containing systems, it is often necessary to add polymerization accelerators, such as peroxides or hydroperoxides, to compositions containing monomers such as dicyclopentenyloxyalkyl methacrylates. This, however, generally diminishes the storage stability of such systems.